This C++ code uses the **ArduinoJson** library to create and...

This C++ code uses the ArduinoJson library to create and populate a JSON document. Here's what it does step by step:

1. StaticJsonDocument<128> doc;:

   • A StaticJsonDocument of size 128 bytes is created. This means it can hold a JSON object or array with a maximum size of 128 bytes. This document is stored in stack memory rather than dynamically allocated memory (heap).

2. doc["Node-id"] = TOF-Level;:

   • A key-value pair is added to the JSON document where the key is "Node-id". The value is set to the value of the variable TOF-Level. This assumes TOF-Level is a previously defined variable.

3. doc["level"] = 134.2;:

   • Another key-value pair is added where the key is "level" and its associated value is 134.2. It's implied that the value represents the sensor's ToF (Time of Flight) reading.

4. doc["battery"] = 3.72;:

   • Another key-value pair is added where the key is "battery" and its value is 3.72. This appears to represent the battery level or voltage in volts.

Output:

After this code is executed, the JSON document doc will contain these key-value pairs:

{
  "Node-id": TOF-Level, // (TOF-Level value is inserted here)
  "level": 134.2,
  "battery": 3.72
}

This document can later be serialized (e.g., converted to a string or sent over a communication protocol) for use in applications such as IoT systems.